19. DNS Resource Records Ch 3 - A an end device address NS an authoritative name server , i.e. a server has resource records that corresponds to its level in the domain hierarchy CNAME the canonical name – an alias name for a host MX mail exchange record
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Editor's Notes
In this chapter, we will focus on the role of one layer, the Application layer and its components: applications, services, and protocols. We will explore how these three elements make the robust communication across the information network possible.
These protocols specify the format and control information necessary for many of the common Internet communication functions.
Within the Application layer, there are two forms of software programs or processes that provide access to the network: applications and services .
All three components may be used by a single executable program and may even use the same name. For example, when discussing "Telnet" we could be referring to the application, the service, or the protocol.
In order for the communications to be successful, the application layer protocols implemented on the source and destination host must match.
The client begins the exchange by requesting data from the server, which responds by sending one or more streams of data to the client. One example of a client/server network is a corporate environment where employees use a company e-mail server to send, receive and store e-mail. The e-mail client on an employee computer issues a request to the e-mail server for any unread mail. The server responds by sending the requested e-mail to the client.
Peer-to-peer networking involves two distinct forms: peer-to-peer network design and peer-to-peer applications. Both forms have similar features but in practice work very differently.
The Hypertext Transfer Protocol (HTTP), one of the protocols in the TCP/IP suite, was originally developed to publish and retrieve HTML pages and is now used for distributed, collaborative information systems.
The e-mail server operates two separate processes: Mail Transfer Agent (MTA) Mail Delivery Agent (MDA)
The e-mail server operates two separate processes: Mail Transfer Agent (MTA) Mail Delivery Agent (MDA)
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